Autonomous cars, or self-driving cars, or driverless cars have been the subject of extensive research and development in recent years. Many big technology companies such as Google, Baidu, and most major car companies including General Motor, Mercedes Benz, and BMW have devoted a lot of resources in this area. All deal with autonomous cars that can travel on public roads and also at highway speeds (more than 40 km/hr). To achieve this requirement, the cars have to be fitted with many expensive sensors to get an understanding of its surroundings. Autonomous cars also keep in constant communication with others and also with a central station to keep tabs on them on the roads close by. For small communities, autonomous cars generally travel at lower speeds (less than 40 km/hr) and the surrounding is less complicated. Less expensive sensors are used and resulted in more reasonably price vehicles. To keep economic factors in mind, a method for autonomous vehicles to be aware of other autonomous vehicles nearby without talking to them directly and without a central station's help, and for making decisions locally without the help of central station and without communicating with other vehicles is strongly needed. This is especially important when traveling through road intersections.
For autonomous cars to go through road intersections whether it is 3-way, 4-way, or more intersection, it is necessary for the autonomous cars to know the position of other autonomous cars to prevent collisions. Traditionally it is for the cars to communicate with each other directly, or have a central station to notify the position of each car.